The tellurite

ion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...

is . A tellurite (compound), for example sodium tellurite, is a compound that contains this ion. They are typically colorless or white salts, which in some ways are comparable to sulfite. A mineral with the formula TeO₂ is called tellurite.

Structure and reactions

Tellurite dianion is pyramidal, like selenite and sulfite. The anion has C_3v symmetry. Tellurites can be reduced to elemental tellurium by electrolysis or a strong

reducing agent In chemistry, a reducing agent (also known as a reductant, reducer, or electron donor) is a chemical species that "donates" an electron to an (called the , , , or ). Examples of substances that are commonly reducing agents include the Earth me ...

. When fused with nitrate salts, tellurite salts oxidize to tellurates (). Upon acidification of aqueous solutions of tellurite salts, solid hydrated

tellurium dioxide Tellurium dioxide (TeO2) is a solid oxide of tellurium. It is encountered in two different forms, the yellow orthorhombic mineral tellurite, β-TeO2, and the synthetic, colourless tetragonal (paratellurite), α-TeO2. Most of the information regard ...

(TeO₂) precipitates. This reaction allows the separation of tellurium from selenium since

selenous acid Selenous acid (or selenious acid) is the chemical compound with the formula . Structurally, it is more accurately described by . It is the principal oxoacid of selenium; the other being selenic acid. Formation and properties Selenous acid is a ...

remains soluble at low pH. The intermediate in the protonation occurs at oxygen to give eO₂(OH)sup>−.

Uses

Potassium tellurite (K₂TeO₃) is used together with agar as part of a selective medium for growth of some bacteria (Clauberg medium).

Corynebacteria ''Corynebacterium'' () is a genus of Gram-positive bacteria and most are aerobic. They are bacilli (rod-shaped), and in some phases of life they are, more specifically, club-shaped, which inspired the genus name (''coryneform'' means "club-shape ...

and some other species reduce to elemental Te, which stains the bacteria black.

References

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Structure and reactions

Uses

See also

References

Further reading